The power produced by a human being is exerted generally through leg movement or arm movement, and in either case, the power occurs in periodic pulses of energy exerted alternately through the left and right body members. Most exercise machines provide separate input mechanisms for the left and right members, and either provide a separate load to work against the energy supplied by the left and right members, or provide a single load for both left and right members of the body. The present invention is directed towards a transmission particularly suitable for combining the input power generated by the left and right body members on a common rotational output to be applied to a load.
There are some training devices in which the power from the left and right body members are combined mechanically, such as in the cycle training device of Quent Augspurger and Charles H. Bartlett of U.S. Pat. No. 4,817,938 entitled Cycle Training Device in which two peddles are interconnected and attached to a drive sprocket in the conventional manner of a bicycle. A similar bicycle type device is disclosed in U.S. Pat. No. 4,824,102 of Peter K. Lo entitled Exercise Bicycle For Exercising Arms And Legs.
A second mechanism for transmitting two separate inputs to a common load is disclosed in U.S. Pat. No. 4,625,962 of Glenn M. Street entitled Upper Body Exercise Apparatus. In this patent, two forces are generated by the hands of the person exercising, and these forces form inputs which are impressed upon a common load driven by a shaft through two separate one-way clutches. The use of two one-way clutches to couple two inputs to a common load has been used in various types of exercise equipment, including stair climbing exercise machines.
The exercise device of the patent to Street is a relatively large device, and the two one-way clutches and load take up considerable space. Manufacturers of exercise devices have been striving for smaller units and units which will provide better feel and more information to the exerciser. Hence, it is an object of the present invention to provide a transmission, which is of considerably smaller size than those previously known, to convert two separate rotational inputs to a common rotational output.
One-way clutch mechanisms for use in converting two inputs to a common output for an exercise machine are subject to considerable wear. Further, such devices must be constructed in a manner which will not require significant service. It is therefore an object of the present invention to provide a one-way clutch transmission for converting two or more rotational sources of energy to a common output which is capable of withstanding long term use and some abuse.
Most exercise machines employ loads which are operated at a speed significantly higher than the speed that the input member attains under drive by the exerciser. Accordingly, such devices have speed increasing drive trains from the input member to the load. For exercise machines, such drive trains incorporate a transmission for combining torque on two input members on a common output member of greater diameter than the input members. It is an object of the present invention to provide such a transmission in which two increased capacity one-way clutches are incorporated in the larger diameter output member, each of the input members being coupled to the output member through one of the one-way clutches.
One of the common causes for clutch wear is failure to maintain concentricity between the inner and outer races of the clutch. It is therefore one of the objects of the present invention to provide an assembly of two or more one-way clutches provided with improved bearing structure to maintain concentricity between the inner and outer races of the clutches.
Exercise devices tend to be costly, and manufacturers of such devices attempt to contain such costs in order to facilitate sales. It is therefore an object of the present invention to provide a transmission for converting two rotational inputs to a single rotational output at a cost reduced from that of such prior transmissions of comparable torque.